If you've ever seen people with red eyes in a photo that was taken with a flashing camera, you've seen this effect. Their eyes being bright red is the result of submarine light reflecting off of the back of their eyes which illuminates blood flowing through their bodies. note Most deep sea creatures have no need for thick skins to protect their organs from ultraviolet radiation from the sun, so theirs tend to be transparent. For example, many creatures do not have eyes or have evolved special eyes due to the lack of light, and are usually either very dark, transparent, or bright red in color. Nevertheless, there is still some Truth in Television to this for a host of different reasons: the environmental conditions (low or no light, high pressure, low temperature, low oxygen, and very little food or prey compared to shallow waters) in the midnight, note 'bathypelagic', around 1,000 to 4,000 meters below sea level, abyssal note 'abyssopelagic', about 4,000 to 6,000 meters below sea level ocean floors are included in this zone, and hadal note 'hadopelagic', extending down to about 11,000 meters below sea level, zones of the ocean have led organisms to evolve traits that are completely different from creatures that evolved on land and even from some shallow water fish. Submersibles and ROVs have allowed closer study of the ocean depths, and oceanographers have not found any Eldritch Abomination or Cthulhu in any part of the sea-floor (yet). Creatures spawned before The Great Flood might be swimming down there, torpid and undisturbed - not disturbed yet, at least.

Great strange beasts that have not set foot on the shore since prehistory might be silently stomping across the silty seafloor. Some surmised that the ocean depths were a sort of Lost World where monsters that had ages ago vanished from the surface could still be alive and hiding. Oceanographers had almost no information to work with, and Nothing Is Scarier. No ray of light can reach that depth, and Dark Is Evil. Until recent technological developments, no one had a chance at observing the deep sea. The ocean floors and trenches have forms of life that are wholly alien to humans: deep sea anglerfish, Giant Squids, gulper eels, chimera fish, to which fiction can add any bizarre variety of horrific leviathan. The really deep, dark parts of the ocean are even more mysterious. We know more about the surface of Mars than we do about our own oceans.

Surviving the abyss monster